DEPAKTMENT OF THE INTEKIOR— U. 8. GEOLOOICAL SURVEY 
J. W. I"()\VEI,I„ DlUKCTol; 



THE 



kmm ELEVATION (IF THE UNITED STATES 



BY 



TTTT/NJKY O^ISTN^ETT 




EXTKACT KKOM THE THIKTKKNTn AXyi^AL HFroin' (iF THE DIRECTOR, 1891-'92 




WASnrXGTON 

OOVKKNMKNT PRINTING (IFFIPE 
1.S04 



1 



i4 



DEPARTMENT OF THE INTEEIOK-U. S. GEOLOGICAL SURVEY. 



THE AVEP.ArxE ELEVATION OF THE UNITED STATES, 



HENRY GANNETT. 



283 



THE AVERAGE ELEVATION OF THE UNITED STATES. 



By Henry Gannett. 



For several years tlie United States Geolofiical Survey has been en- 
gaged in the coinpilation of measurements of altitudes of i)oints in the 
United States, primarily for use as datum poiuts in connection with 
the preparation of its detailed maps. The results of this compilation 
have from time to time been published in the form of a dictionary of 
altitudes, the first edition of which constituted Bulletin No. 5 and a 
second edition Bulletin No. 76. As a by-product, a map of the United 
States upon a scale of 0-5000701 or about 40 miles to an inch, has re- 
cently been published showing approximate contour lines at the fol- 
lowing elevations above sea level: 100, 500, 1,000, l,.->00, 2,000, 3,000, 
4,000, .5,000, 0,000, 7,000, 8,000, 9,000, 10,000, 11,000; and 12,000 feet. 
From this map has been produced by reduction the map presented in 
this volume as Plate cvii. 

These contour lines were constructed from the following material : 

(1) By reduction and generalization of (iontour maps from surveys 
upon much larger scales. In the poi'tion of the map contoured by 
this means the contours can be regarded as correct. The maps thus 
used are enumerated as follows: 

The maps of the United States Geological Survey of the Hayden, 
Powell, and King (Fortieth Parallel) surveys in the West, the Northern 
Transcontinental survey, the New Jersey Geological survey, and the 
Minnesota Geological and Natural History survey. 

These maps suthced to contour the f(»Ilo\ving areas : All of Massachu- 
setts, Rhode Island, New Jersey, and District of Columbia, western 
Couuecticut and Maryland, most of Virginia and West Virginia, west- 
ern North Carolina, eastern Tennessee, eastern Kentucky, northern 
Georgia and northern Alabama, the southern half of Minnesota, most 
of Missouri, part of the O/ark Hills of Arkansas, the eastern half of 
Kansas, central Texas, the mountain region of Colorado, all of Utah, 
the northern half of Arizona, northwestern New Mexicp, parts of Wy- 
oming, Idaho, Montana, Nevada, and Washiugton-with northern Cal- 
ifornia and southern Oregon, besides trifling areas in other states. 
These areas comprise much the greater part of the mountainous and 
284 



D. ot 0. 



GANNETT.) DESCRIPTION OF THE MAP. 285 

most difficult regions. Altogether about oue-fiftL of the area of the 
couutry was contoured by thi.s means. 

(-) % platting the conn.il.-d iiicasureiirents of altitude uixm maps 
and sketching contours witli ri'ference to these measurements, using 
the best available hachure maps as guides in interpreting the measured 
lieights and in I. .eating contimrs l)et\veen them. Tiiis method, wliich 
was used in compiling mucli the greater ].ortion of the map, has natu- 
lally produced results differing greatly in ditterent region.s with the 
density of distribution of the measurementsof heights and witli the char- 
acter of surface, whetlier mountainous or plain, and witli the knowledge 
possessed of the surfiice. About 25,000 measurements of height have 
been so used, an average, if they were uniformly distriliuted, of about 
12 to a square inch of the map. This number of measurements, com- 
bined with a knowledge of the relief of the country, would be adequate 
for the location of contours with a liigh degree of accuracy almost any- 
where in tlie country. They are not, however, distributed by any means 
uniforndy. A great majority of them are from railroad levels, and 
consequently the east is much better represented than the west. The 
level prairies of Illinois are intersected by a perfect network of railroad 
lines, while in the Cordillerau region, the raih-oads are separated by 
broad areas of mountain and valley. In this region, however, the 
d measurements of heigfit is suiipliaiented by baro- 
metric rn. maiie l)y tlie mmierous exi>l.irations under 
* "• '•'-' notably that known as the VVTieeler survey, 
iu>se ctoelleut maps and measurements have been used wherever 
a\aihible. Theio reintVUi, ii,>,\o\er, cwtaiu areas coucerninc which 
little information of any kind is to be had. 

The contoiu-s of the map may be classified with respect to their 
probable accuracy into four groups. 

A. Correct. Those areas reduced from contour maps. 

B. Very nearly correct. The Atlantic Slope, east of the Blue Ridge ; 
the entire Mississippi A'alley, to the base of the Rocky Mountains 
and of the Staked Plains; the region of tiie Great Lakes; the valleys 
of California and Oregon. 

C. Approximately correct. The remainder of New England, except 
northern Maine. New York except the Adirondack region. Pennsyl- 
vania and the Cordillerau region, except the areas enumerated below. 

D. Hypothetical. Northern Maine, Adirondack region of New York, 
central Idaho, the Cascade range and the Coast range of AYashington, 
Oregon and northern California. 

From the map, the strengtli and weakness of wliicli have been char- 
acterized above, the areas between the various contour lines have been 
measured with considerable care up to 10,000 feet. Above tliat altitude 
the areas are so small in all the States except Colorado, that they have 
been grouped under the heading " Above 10,000 feet." The results are 
given below. 



286 THE AVERAGE ELEVATION OF THE UNITED STATES. 

Table I. — Arvim hctwein 
lAltitudc in feet; 



States and Territoriea. 


0-100. 


100-500. 


500-1,000. 
14,240 


1,000-1,500. 


1 1,500-2,000. 

1 


2,000-3,000. 




4,400 


30,000 


3. GOO 
6,900 
6,000 
11,400 


610 
8,200 
3,600 
13,800 






15.600 

700 

17,400 






35, 200 


8.350 




11.000 














1, 100 

1,900 

20 

44,800 

5,900 


2,000 

150 

50 

13.880 

29, 600 


1,230 


660 


















Florida 


1 ■ 1 






16, 300 


5,400 














5,800 


Uliiioia 




11,900 
4,700 


44,750 
28,800 
19, 600 
8,300 
26,900 










2 850 












35,845 
25,900 
4,100 


78o' 










13,900 
1.300 


19,600 






8.000 




34,000 


14, 720 








6.000 
7, 400 


lU. Sou 
2,000 


8.400 
1,700 


6.740 
300 


1,100 

410 




Maryland 


400 


Massacbuaetts 


2,000 


3,265 


1,800 


1,150 


100 










45 700 


11 515 


1 700 


* 








10 400 


59,365 


7 600 




Mississippi 


4,000 


41,510 


1.300 














1,375 
35,600 
14, 300 












1,000 


34.600 

24,510 

5,400 

400 










11,700 










Sew Hampshire 


400 


1,955 


2.800 


2.800 


800 




4,100 


2,100 


1.400 


215 














1,200 
1,700 


New York 


2.400 


• 10,900 


16. 100 


12,500 


5,170 




18, 700 


13 100 


10.000 
5.800 


3.200 
12.200 


1 000 


3 100 


North Dakota 






25, 300 


26, 895 


Ohio 




760 


29, 800 
33, 130 


10 500 






^ludian Territory i 

(Oklahoma .* i 




1,800 


10, 400 


9,000 


6.500 




Oregon 


1,700 


8,800 


9,800 


6, 2(10 


6.300 


6,700 


Pennsylvania 


600 


5,500 


12, 700 


15. 9(H) 


8.215 


2.300 




470 
10,600 


650 
10. 900 


130 

8,100 

270 








South Carolina 


90IP 
18. 100 


70 
24. 200 




South Dakota 


23,000 
1 150 


Tennessee 




lo 400 


15,800 
39,380 


7 600 


4 900 


Texas 


23,600 


58.400 


19 800 


''2 200 


44 100 


Utah 








l.OOU 






1,965 
10, 500 


3.600 
5.950 


2 600 




Virginia 


9.700 


4,700 


4 200 


6,800 




5,000 


6, 000 


9. 000 


18,000 

6,000 

24, 640 




8,000 
5 280 








4,200 
4,800 








26.600 




Wvoniing 















1 




199. 790 


388. 305 


515,770 


390. 08U 


240,510 


262,635 1 

■ ■ ■ 1 





ALTITUDES BY STATES. 



287 



different detfrees of aHititdc. 
area in siiuarc miles.] 



3,000-4,000. 


4,000-5,000. 


5,000-6,000. 


6,000-7,000. 


7,000-8,000. 


8,000-9,000. 


9,000-10.000. 


Above 
10. 000. 



















12,500 


13,600 


23,900 


10,520 


6.100 


500 


200 




14, 000 
4.30O 


16.500 
22, 700 


13,500 
17, 100 


8.30O 
12. 725 


4,800 
13,500 


3.400 
11.500 


1.800 
8,600 


1,700 
12.900 


































































14,500 


26. 150 


21.900 


10, 600 


4,540 


800 


10 























. 














14,200 


180 























i 



























1 




























i 1 








1 





































7.800 








150 
















* 




1 




6.000 
200 

2,650 
600 


34,200 
200 
400 


31, 280 


25. 400 


18, 500 


4,000 1,400 


600 


100 





























1,800 1.800 












16.900 


5.200 


730 


211(1 










































8.000 

200 

20.100 

500 


1,800 


700 


500 


180 












29,800 
24,900 


2,000 

21, 100 


400 
15.970 










10.800 


6,200 


2. 800 


1,700 


600 
6.000 
1,200 
















3,300 

200 

11,100 


1,200 


500 


69 













22.000 


26.500 


23,290 


8.600 • 4.100 


2,300 
















182.800 1 263,830 


215, 100 159. 515 


93.109 ;I9,0U0 19,110 19,200 



288 THE AVERAGE ELEVATION OF THE UNITED STATES. 

From this table it appears that no considerable i)art of Delaware, 
Uistrift of Columbia. Louisiana or Kiiotle Islainl exceeds 500 feet above 
sea level: that in fllinois and Mississippi there is no area above 1,000 
feet: that in Connecticut, Indiana, Xcw Jersey and Ohio, no part of the 
surface is above 1,.")0() feet, that the 2, 0011-foot contour is not found in 
Alabama, Iowa, Maine, Massachusetts, Michigan, Minucsota, Missouri, 
South Carolina or Wisconsin, the ;5.000-foot in Arkansas, Georgia, Ken- 
tucky, Maryland or Pennsylvania, the 4.000-foot in Xorth Dakota, Ten- 
nessee, Vernu)nt or Virginia, the .">, 000-foot contour in Kansas, New 
Hampshire, New York, Indian Territory or West Virginia. The 0,000- 
foot contour is the highest represented east of the Cordilleran region 
and includes no areas of magnitude in Nebraska or North Carolina- 
The 7,000foot contour overtops the highest areas in Texas; that of 
8,000 feet is above the summits of the Black Hills, the highest laud in 
South Dakota, and above all considerable areas in AVashingtou; while 
that of l>,00(t feet overlies all considerable areas, so far as known, in 
Idaho, Nevada, and Oregon. The contour of 10,000 feet is higher than 
any extended area in Arizona and Montana, while in the States of Cali- 
fornia, Colorado, New Mexico. Utah and Wyoming, are extensive areas 
above this contour line. 

On the other hand, the entire state of Wyoming lies above the cont<mr 
of 4,000 feet, Colorado lies above tliat of 3,000 feet and Nevada, New 
Mexico and Utali above the 2,0(»0-foot line. Idaho and Montana are 
entirely above the contour of 1,000 feet, while above the 500-loot line are 
the entire areas of Iowa, Kansas, Michigan, Minnesota, Nebraska, 
North and South Dakota, West Virginia and Wisconsin. The lower 
limits of Arizona, Arkansas, Illinois, Indiami, Kentucky, Missouri, 
Ohio, ludian Territory, Tennessee aud Vermont, are fouud to be more 
tlian 100 feet above the sea. The remaining states extend nearly or 
quite to sea level. , 

Of all the states, California has the widest range in altitude, extend- 
ing from sea level to nearly 15,000 feet with a considerable area above 
10,000 feet. Of all the states Colorado has luuch the largest area above 
10,000 feet, an area considerably in excess of that of all other states, 
combined, and whereas in the other states this elevated area consists 
merely of mountain ranges, in Colorado there are broad stretches of 
plateau and extensive mountain valleys, above this altitude. 

In the following table is ])resented an approximation to the mean or 
average elevation of each state and territory of the United States. 
These have been deduced in part from the figures of Table I, in ])art 
from other data. 

The average elevation of the United States and of such of the states 
as i^resent a considerable range of elevation, has been determined fi-om 
this Table I, in the following manner: The area between two consec- 
utive contour lines has been assumed to have an average elevation 
halfway between these contours. Thus, in C(dorado the area between 



MEAN ELEVATION BY STATES. 



289 



5,000 and 6,000 feet has been assumed to have a mean elevation of 5,500 
feet. This assiiiiii)ti(>u is not absolutely correct, but, as shown by Mr. 
Murray (Scottish Geographit; Magazine), it involves no serious error. 
The areas between consecutive contours were then multiplied by these 
assumed average elevations, the several products added together, and 
their sum divided by the total area of the state or country. 

In cases where the range of elevation is but slight, as in Delaware, 
Florida, and tlie District of Columbia, the mean elevation was obtained 
by taking the mean of all measured altitudes witliin its limits. Inas- 
much as these states are in the eastern half of the country, and the 
measurements of height within their limits are numerous and well dis- 
tributed, the average elevations of these states are well determined. 

Taiii.k II. — Mean elevation. 



\ 



State and Territory. 



Alabama 500 

Arizona 4, 100 

Arkansas 650 

California 2, 900 

Colorado G, 800 

Connecticut r»UO 

Delaware ' 60 

District of Colnmbia 150 

Fl.iiida 100 

Georgia noo 

Idaho 5. 000 

niinois 60O 

Indiana 700 

Iowa 1,100 

Kansas 2,000 

Kentucky 750 

Louisiana 100 

Maine 600 

ifaryland 350 

Massachnsetta 500 

Michigan 900 

Minnesota 1,200 

Mississippi j 30O 

Missouri | 800 

Montana I 3, 400 

Nebraska 2,600 



Feet. 



State and Territory. 



Ty > 



Nevada 5, 500 

Xcw Hampshire 1,000 

New Jersey 250 

New Mexico 5, 700 

New York 90U 

North Carolina 700 

NorthDakota 1,900 

Ohio 850 

Indian Territory 
Oklahoma 

Oregon 

Pennsylvania . . 
Rhode Island . . 
South Carolina 
South Dakotii. 

Tennessee 

Texas 1,700 

Utah 6,100 

Vermont ] 1, 000 

Vir;;inia 950 

Washington 1,700 

West Virginia 1 . 500 

Wisconsin ] 1, 050 

Wyoming ' 0, 700 

United Stales 2,500 



Feet. 



1.300 

3,300 

1,100 

200 

350 

2,200 

900 



From this table it appears that Colorado has the greatest average 
elevation of all the states and territories. Wyoming follows closely, 
then Utah, with New Jlexico and Nevada, all of these having an average 
elevation greater than 5,00(1 feet. 

13 GEOL., PT. li 19 




II. 
balfw . 



